ON  EXTRACTUM  EERRI  POMATUM. 
27 
that  the  iron  will  be  retained  in  the  state  of  protoxide  while  the 
same  object  is  accomplished  by  the  second  method  until  the 
evaporation  is  carried  on  in  a  porcelain  dish,  when  an  oxida- 
tion of  at  least  a  part  of  the  iron  to  sesquioxide  is  unavoidable. 
The  extract  is  very  often  given  in  solution,  by  itself,  and  as 
an  addition  to  mixtures  ;  it  is  therefore  desirable  to  have  it  in 
such  a  state  as  to  form  a  perfect  solution  of  such  a  stability  as  not 
to  cause  a  precipitate  of  oxide  of  iron,  or  otherwise  to  deteri- 
orate. The  malate  of  the  protoxide  of  iron  is  hardly  known  yet, 
but  is  said  not  to  be  so  easily  soluble  as  the  same  salt  of  the  ses- 
quioxide of  iron,  and  in  accordance  with  that  chief  object  of  ob- 
taining an  extract  of  perfect  solubility  and  stability,  it  must  be 
aimed  at  to  get  rid  of  all  those  constituents  of  apple  juice,  which 
like  albumen,  would  tend  to  deterioration,  and  to  obtain  much  of 
the  iron  in  the  state  of  sesquioxide.  All  this  is  gained  by  the 
latter  part  of  the  process  of  the  Prussian  Pharmacopoeia,  which 
directs  an  evaporation  in  a  porcelain  dish  at  a  temperature  which 
would  coagulate  albumen,  and  a  redissolving  of  the  extract,  fil- 
tering and  again  evaporating.  The  extract  prepared  in  this  way 
is  of  a  greenish  black  color,  is  entirely  soluble  in  water,  without 
forming  any  precipitate  on  standing  or  on  exposure  to  the  air ;  it 
contains  both  proto-  and  sesquioxide,  probably  the  magnetic  Ox- 
ide of  iron.  The  directions  of  the  Prussian  Pharmacopoeia  may 
therefore  be  followed  with  some  slight  modifications,  and  the  pro- 
cess will  then  be  as  follows  : 
Take  of  unripe  apples,  peeleds'and  mashed  to  a  pulp  6  lbs  ;  clean 
iron  filings  Jib,  mix  and  digest,  stirring  occasionally  until  the  pulp 
has  but  a  slight  acid  reaction,  express  the  liquor,  strain  and  evap- 
orate it  at  a  temperature  not  exceeding  163°  F.,  stirring  con- 
stantly to  the  consistence  of  an  extract ;  redissolve  this  in  four 
times  its  weight  of  distilled  water,  filter  and  again  evaporate  with 
the  precaution  mentioned,  to  the  proper  consistence. 
The  liquid  preparation  of  this  extract  is  called  Tinctura  Ferr 
Pomati  s.  Pomata,  and  is  obtained  by  dissolving  one  part  of  the  ex- 
tract in  six  parts  by  weight  of  vinous  cinnamon  water,  which  con- 
tains nearly  J  its  weight  of  alcohol.  This  tincture  is  of  a  green- 
ish black  color,  with  a  brown  tinge  and  of  a  sweetish,  slightly 
stiptic  taste;  it  remains  clear  without  separating  any  sediment. 
The  active  constituent  of  these  preparations  is  the  malate  of 
iron,  mixed  with  some  sugar  and  extractive  matter  ;  it  is  one  of 
